Online conversations on the Internet may influence parents’ decision-makingprocess regarding vaccination. Therefore, it is essential to understand whatparents discuss and how they are advised about vaccinations in online com-munities. This qualitative study explores online conversations concerningthe measles, mumps and rubella (MMR) vaccine among members of a Swe-dish anti-vaccination community on the social media platform Facebook.We found that negative, erroneous, and pseudoscientific notions of vacci-nations were common and often related to broader understandings of childhealth. Members generally overlooked the beneficial societal aspects of thevaccination. To create trust among parents concerning the MMR vaccine,Swedish healthcare personnel should be given the means and resources topromote the beneficial aspects of the vaccination in relation to parents’ riskperceptions as well as to scientifically based arguments and understandings